Chemokines are chemotactic cytokines, of molecular weight 6-15 kDa, that are released by a wide variety of cells to attract and activate, among other cell types, macrophages, T and B lymphocytes, eosinophils, basophils and neutrophils (reviewed in Luster, New Eng. J Med., 338, 436-445 (1998) and Rollins, Blood, 90, 909-928 (1997)). There are two major classes of chemokines, CXC and CC, depending on whether the first two cysteines in the amino acid sequence are separated by a single amino acid (CXC) or are adjacent (CC). The CXC chemokines, such as interleukin-8 (IL-8), neutrophil-activating protein-2 (NAP-2) and melanoma growth stimulatory activity protein (MGSA) are chemotactic primarily for neutrophils and T lymphocytes, whereas the CC chemokines, such as RANTES, MIP-1α MIP-1β, the monocyte chemotactic proteins (MCP-1, MCP-2, MCP-3, MCP-4, and MCP-5) and the eotaxins (-1, -2, and -3) are chemotactic for, among other cell types, macrophages, T lymphocytes, eosinophils, dendritic cells, and basophils. There also exist the chemokines lymphotactin-1, lymphotactin-2 (both C chemokines), and fractalkine (a CXXXC chemokine) that do not fall into either of the major chemokine subfamilies.
The chemokines bind to specific cell-surface receptors belonging to the family of G-protein-coupled seven-transmembrane-domain proteins (reviewed in Horuk, Trends Pharm. Sci., 15, 159-165 (1994)) which are termed “chemokine receptors.” On binding their cognate ligands, chemokine receptors transduce an intracellular signal through the associated trimeric G proteins, resulting in, among other responses, a rapid increase in intracellular calcium concentration, changes in cell shape, increased expression of cellular adhesion molecules, degranulation, and promotion of cell migration. There are at least ten human chemokine receptors that bind or respond to CC chemokines with the following characteristic patterns: CCR-1 (or “CKR-1” or “CC-CKR-1”) [MIP-1α, MCP-3, MCP-4, RANTES] (Ben-Barruch, et al., Cell, 72, 415-425 (1993), Luster, New Eng. J. Med., 338, 436-445 (1998)); CCR-2A and CCR-2B (or “CKR-2A”/“CKR-2B” or “CC-CKR-2A”/“CC-CKR-2B”) [MCP-1, MCP-2, MCP-3, MCP-4, MCP-5] (Charo et al., Proc. Natl. Acad. Sci. USA, 91, 2752-2756 (1994), Luster, New Eng. J. Med., 338, 436-445 (1998)); CCR-3 (or “CKR-3” or “CC-CKR-3”) [eotaxin-1, eotaxin-2, RANTES, MCP-3, MCP-4] (Combadiere, et al., J. Biol. Chem., 270, 16491-16494 (1995), Luster, New Eng. J. Med., 338, 436-445 (1998)); CCR-4 (or “CKR-4” or “CC-CKR-4”) [TARC, MIP-1α, RANTES, MCP-1] (Power et al., J. Biol. Chem., 270, 19495-19500 (1995), Luster, New Eng. J. Med., 338, 436-445 (1998)); CCR-5 (or “CKR-5” OR “CC-CKR-5”) [MIP-1α, RANTES, MIP-1β] (Sanson, et al., Biochemistry, 35, 3362-3367 (1996)); CCR-6 (or “CKR-6” or “CC-CKR-6”) [LARC] (Baba et al., J. Biol. Chem., 272, 14893-14898 (1997)); CCR-7 (or “CKR-7” or “CC-CKR-7”) [ELC] (Yoshie et al., J. Leukoc. Biol. 62, 634-644 (1997)); CCR-8 (or “CKR-8” or “CC-CKR-8”) [I-309, TARC, MIP-1β] (Napolitano et al., J. Immunol., 157, 2759-2763 (1996), Bernardini et al., Eur. J. Immunol., 28, 582-588 (1998)); and CCR-10 (or “CKR-10” or “CC-CKR-10”) [MCP-1, MCP-3] (Bonini et al, DNA and Cell Biol., 16, 1249-1256 (1997)).
In addition to the mammalian chemokine receptors, mammalian cytomegaloviruses, herpesviruses and poxviruses have been shown to express, in infected cells, proteins with the binding properties of chemokine receptors (reviewed by Wells and Schwartz, Curr. Opin. Biotech., 8, 741-748 (1997)). Human CC chemokines, such as RANTES and MCP-3, can cause rapid mobilization of calcium via these virally encoded receptors. Receptor expression may be permissive for infection by allowing for the subversion of normal immune system surveillance and response to infection. Additionally, human chemokine receptors, such as CXCR4, CCR2, CCR3, CCR5 and CCR8, can act as co-receptors for the infection of mammalian cells by microbes as with, for example, the human immunodeficiency viruses (HIV).
Chemokine receptors have been implicated as being important mediators of inflammatory, infectious, and immunoregulatory disorders and diseases, including asthma and allergic diseases, as well as autoimmune pathologies such as rheumatoid arthritis and atherosclerosis. For example, the chemokine receptor CCR-3 plays a pivotal role in attracting eosinophils to sites of allergic inflammation and in subsequently activating these cells. The chemokine ligands for CCR-3 induce a rapid increase in intracellular calcium concentration, increased expression of cellular adhesion molecules, cellular degranulation, and the promotion of eosinophil migration. Accordingly, agents which modulate chemokine receptors would be useful in such disorders and diseases. In addition, agents which modulate chemokine receptors would also be useful in infectious diseases such as by blocking infection of CCR3 expressing cells by HIV or in preventing the manipulation of immune cellular responses by viruses such as cytomegaloviruses.
A substantial body of art has accumulated over the past several decades with respect to substituted piperidines, piperizinones and pyrrolidines. These compounds have implicated in the treatment of a variety of disorders.
WO 98/25604 describes spiro-substituted azacycles which are useful as modulators of chemokine receptors: wherein R1 is C1-6 alkyl, optionally substituted with functional groups such as —NR6CONHR7, wherein R6 and R7 may be phenyl further substituted with hydroxy, alkyl, cyano, halo and haloalkyl. Such Spiro compounds are not considered part of the present invention.
WO 95/13069 is directed to certain piperidine, pyrrolidine, and hexahydro-1H-azepine compounds of general formula: wherein A may be substituted alkyl or Z-substituted alkyl, with Z=NR6a or O. Compounds of this type are claimed to promote the release of growth hormone in humans and animals.
U.S. Pat. No. 5,753,654 discloses Gastrointestinal prokinetic agents for the treatment of digestive tract diseases directed toward compounds of the general formula: wherein R1 is H, cycloalkyl, alkyl and others, R2 is a group of several different heterocycles optionally linked via methylenes, and R3 is H, alkyl, and others.
WO 01/68604 is directed to such cyclic ring systems including piperidines, pyrrolidine and morpholine compounds of general formula: wherein R3 may be substituted alkyl, aryl, alkenyl, and others and R1 may be substituted with H, alkenyl, (hetero)aryl, (hetero)aralkyl, and others. Compounds of this type are claimed as ligands for various cellular receptors including opioid receptors, other G-protein-coupled receptors and analgesics.
U.S. Pat. No. 5,668,151 discloses Neuropeptide Y (NPY) antagonists comprising 1,4-dihydropyridines with a piperidinyl or tetrahydropyridinyl-containing moiety attached to the 3-position of the 4-phenyl ring: wherein B may be NH, NR1, O, or a bond, and R7 may be substituted phenyl, benzyl, phenethyl and the like.
Patent publication EP 0 903 349 A2 discloses CCR-3 receptor antagonists comprising cyclic amines of the following structure: wherein T and U may be both nitrogen or one of T and U is nitrogen and the other is carbon and E may be —NR6CONR5— and others.
WO 97/27752 discloses compounds of the general formula: wherein W may be a pyrazole ring. These compounds are claimed to treat cancer as inhibitors of farnesyl-protein transferase.
WO 99/04794 is directed towards modulators of chemokine activity having the general formula: wherein the claimed compounds are para-substituted piperidines.
WO 94/22846 discloses compounds having the general formula: and optionally having the R101 and R102 connected to form a heterocycle ring. These compounds are disclosed as agents for sensitizing tumor cells or as anti cancer agents.
PCT publications WO 00/35451 and WO 01/98269 discloses compounds having the general formula wherein the compounds are modulators of chemokine receptor activity.
These reference compounds are readily distinguished structurally by the present invention. The prior art does not disclose nor suggest the unique combination of structural fragments which embody these novel piperidines as having activity toward the chemokine receptors.